Nosocomial infections are tough issues. Generally, the nosocomial infection rate is about from 3% to 5%. Organisms causing nosocomial infections are usually opportunistic pathogens. In other words, these bacteria are not harmful to hosts with normal immunity, and some of them are even normal flora to human; however, while hosts have weak immunity, the bacteria cause infections, resulting in diseases.
The common bacteria causing nosocomial infections include Staphylococcus, Pseudomonas, Acinetobacter, Enterococci, Enterobacteriaceae, Non-fermentative gram-negative bacilli, Legionella, Clostridium, Mycobacterium, etc.
Currently, the most common bacteria causing nosocomial infections include Pseudomonas aeruginosa, Staphylococcus aureus, Acinetobacter baumannii, etc.
Bacteria causing nosocomial infections may exist in stethoscopes, anamnesis papers, tourniquets, grooves, syringe needles, respirators, humidifiers, furniture, floors, vents, monitors, water, soil, food (fruits, vegetables), dirt in drainage, human body such as skin, armpits, mucosal, oral cavity, upper respiratory tract, nasal cavity, gastrointestinal tract, etc.
For example, nosocomial infections occur in an intensive care unit since patients in the intensive care unit have weak immunity and have invasive therapies such as being cannulated. According to statistics, the nosocomial infection rate in an intensive care unit is about from 2% to 3%.
Antibiotics are general therapeutic agents for treating bacterial infections. However, when antibiotics are overused, bacteria will be selected to have resistance to the antibiotics. In current nosocomial infections, there are more and more bacteria having resistance to antibiotics, and patients infected by these bacteria have to be treated with expensive and novel antibiotics. Further, if the antibiotic resistance keeps developed, there will be no effective antibiotic for therapy. Hence, it is necessary to develop a method and/or a composition for reducing and/or preventing nosocomial infections.
Phages (bacteriophages) are viruses that infect bacteria, and grow and replicate in bacteria. There are lytic phages and lysogenic phages. Lytic phages infect bacteria, replicate in bacteria, and then are released from the bacteria by lysing and killing the bacteria. Lysogenic phages are capable of undergoing lytic or lysogenic life cycles, and exist in host cells while in lysogenic life cycles.
It has been disclosed that bacterial diseases are treated by with phages. For example, U.S. Pat. Nos. 5,688,501,5,997,862, 6,248,324 and 6,485,902 have disclosed a pharmaceutical composition comprising phages for treating bacterial diseases, group A streptococcal infections, dermatological infections, and control of Escherichia coli O157 infections, respectively. U.S. Pat. No. 6,121,036 has disclosed a pharmaceutical composition having at least one phage. U.S. Pat. No. 6,699,701 has disclosed using Salmonella enteritidis—specific phages for packing food, in which a package material is coated with phages, and food (such as fruit and vegetables) is packed with the package material.
Accordingly, in the current applications of phages, there is no method for preventing or treating bacteria that cause nosocomial infections. Particularly, there are no phages of Acinetobacter baumannii and methods for reducing the amount of Acinetobacter baumannii (abbreviated as AB, hereafter) that cause nosocomial infections in prior art.